The target community for this study is youths age 8-18 with developmental disabilities (DD) and their families. The significance lies in the overall health equity issue it addresses: the higher prevalence rates of obesity in youth with DD than in those who develop typically, which is of great concern due to many associated health risks. Increased levels of physical activity (PA) is a factor that is known to reduce obesity risk in children, but in our earlier survey of parents, less than 20% were definitely satisfied with available opportunities, and children with DD are known to be disadvantaged regarding participation in PA relative to typically-developing peers. Thus the project focuses on PA as a critical element in reducing obesity risk, and assumes that improving children's opportunities for PA can be the hook for education about diet, nutrition, and the need to reduce sedentary activity, all important aspects of achieving and maintaining healthy weight. The four Specific Aims will involve our community partners in every phase of research to: 1) Determine the cultural, psychosocial and socioeconomic circumstances that impact parents' ability and enthusiasm for facilitating their children's participation in PA. 2) Identify, for youths with varing functional limitations and developmental as well as chronological ages, their self-reported preferences for various PAs and the social contexts within which they are offered. 3) Ascertain potential PA sites, trainers and mentors in the community to comprise a network of sustainable activities, venues and personnel, and 4) Evaluate several small-scale PA interventions that are developed and implemented based on the results of Aims 1 - 3. The study is unique in using Self- Determination Theory (SDT) as its framework. SDT, which has been gaining currency in PA programs, suggests that activities performed for their inherent rewards foster more adaptive outcomes than those performed for extrinsic rewards. According to SDT, fulfillment of three psychological needs is critical to optimal motivation: autonomy, competence, and relatedness. This model most closely mirrors our community members' beliefs that to be sustainable, PA programs must include choice of activity and setting (autonomy) and ongoing mentor/trainer support (relatedness) in addition to competence. Although there have been suggestions about the usefulness of SDT in PA programs for children with disabilities, to our knowledge this is the first study to base an intervention on its framework. In our information gathering from parents we will use Ajzen's Theory of Planned Behavior, an extensively validated model that proposes that the intention to perform a behavior is affected by attitude toward the behavior, subjective norms, and perceived behavioral control. If successful, we anticipate our study will lay the groundwork for more comprehensive efforts to implement and evaluate similar programs to reduce obesity in youth with DD through PA programs in larger controlled trials.